People who have recurring nightmares are at greater risk of developing dementia, according to the results of a recent study.
When you consider that we spend almost 6 years dreaming (for an average life expectancy of 73 years), it’s not surprising to suppose that this brain activity has a real impact on the brain in the long term.
According to the researchers’ findings, recurrent nightmares promote dementia, « a syndrome in which there is a deterioration in memory, reasoning, behavior and the ability to carry out daily activities » and which affects almost 50 million people worldwide, as the WHO reminds us.
A link between repeated nightmares and dementia?
Scientists at the University of Birmingham have hypothesized that regular nightmares are a warning sign of dementia.
Published in The Lancet eClinicalMedicine, the study was carried out in the USA on over 600 people aged 35 to 64 (who were followed for 9 years) and 2,600 people aged 79 and over (followed for 5 years). None of them had cognitive problems at the start of the survey.
The aim? To establish a possible link between the recurrence of these bad dreams and the risk of cognitive decline , using data collected by participants via a questionnaire.
The results show that having nightmares once a week on average affected the brain capacity of the first group, and put them at four times greater risk of dementia in the ten years that followed.
For the second group of older people, the risks were twice as high.
A difference between men and women
The researchers also noted that nightmares have a different impact on the brains of men and women.
While the oldest male subjects were five times more at risk of dementia when they reported recurring nightmares, equally old women were at less risk (41%).
This difference was also observed among middle-aged participants, although the scientists were unable to provide any real explanation for the discrepancies.
A study that advances research on cognitive decline
Although the researchers believe that the link between nightmare frequency and dementia risk has not been proven, further research could confirm this theory and thus offer new screening possibilities.
« Distressing dreams or nightmares may be linked to dementia risk and cognitive decline in healthy adults in the general population. This is important because there are very few risk indicators for dementia that can be identified as early as mid-life, » notes Dr. Abidemi Otaiku, lead author of the study, in a press release.
All the more so since previous studies had already established a link between poor-quality sleep and increased levels of proteins involved in Alzheimer’s disease.
« If we can identify subjects at high risk of dementia years or even decades in advance, we may be able to slow their decline or even prevent it from occurring, » concludes the expert.